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Total newbie question motor position

Old 10-25-19, 09:03 PM
  #1  
PreacherG
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Total newbie question motor position

Hello. First post here. I am familiar with the GREAT advise available on forums like this. I come knowing very little about e bikes. In my younger years, I rode as my primary mode of transportation, but due to health, I have not ridden at all in 30 years. I think an E bike would be a great way to get around when we go camping, both around the campground and nearby trails. Right now, I barely know enough to ask intelligent questions. Please be gentle.

I understand the mechanical difference of front hub, rear hub and mid motor designs. When riding an E bike, what difference do these styles make in ride, handling, braking, etc.

I assume a mid motor design takes advantage of the gearing of the derailleur or internal hub gearing.

Thanks in advance for this education.
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Old 10-25-19, 09:54 PM
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My experience includes owing a front drive, one mid drive and several rear drives. Most of these are home built conversions, all inexpensive. And all in the context of ridng in a flat area, mostly under 15 mph.

Front drive is mainly for smooth pavement. Most forks with shocks aren't strong enough for the added weight of a front drive, so it's not good for mild trail or bad streets where the added banging/crunching will stress the axle. Does make the front of bike feel heavy when lifting. Can slip on loose surfaces starting out or going uphill. If you're going to buy a bike, not many front drives anyway.

I see no negatives with my Mid drive, other than it was my expensive kit. One has to keep riding it like a bike though, i.e., downshift to low gear when coming up to a stop so the bike an start easier.Keep it at a high spin rate going up long hills.

Rear drive also has little tradeoffs.

I guess my main advice is to avoid front drive. Some people and a few companies make it work, but why choose the weakest link approach for your first venture into ebiking,

Last edited by Doc_Wui; 10-26-19 at 10:47 AM.
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Old 10-25-19, 11:16 PM
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Go test ride some bikes and see which motor position works for you. Your weight, the terrain, etc., all will impact how it rides.
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Old 10-26-19, 02:04 PM
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Good advice ^^^. Since it's doubtful you'll be riding severe hills or technical off road, probably a rear hub motor will be the best option. Only reason in general for front hub is IGH (internal gear rear hub), belt drive or cargo bike IMO.
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Old 10-26-19, 03:26 PM
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The more recent conversion is an early '90s Trek 720 with 38-622 tires on Velocity Dyad rims, using a 36V 500W TSDZ2. No throttle, torque sensor BB - you have to pedal to get assist. Assist levels are 50%, 100%, 200% and 400% increase in torque, limited to a maximum current of 12A (user selectable, default is 16A, but I want to preserve the gear). With the 42T chainring, and 12-36 9 speed cassette, I am limited to a bit above 20 mph due to my limited pedalling speed. I have a 52T chainring on order, which will push it over 25 mph. On a 12-14 AH, 36V battery, I am using less than half the charge for a round trip (no charging at work). The bike is ~25 lbs lighter than the BEAST, is much more relaxing to ride.

I have no ground clearance worries for my commuting - and would choose the TSDZ2 over any other conversion, because of the torque sensor system and its low weight.

If ground clearance is a concern, neither BaFang nor Tong Sheng are good choices because they hang down below the BB.
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Old 12-04-19, 07:47 AM
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In my experience, when choosing a motor location I first, ask who’s going to be using the bike. Is this going to be a bike for a young or elderly person?

For older people, installing the motor on the front wheel is more beneficial. For young people, it’s better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.

In front hub motors the motor drives the front wheel and you can add to that by applying pedal power. If the motor is installed in the front hub, then the wheel can sometimes slip because the front wheel is less loaded.
One big advantage of the front hub motors is that they have a simple design. If you need to change the tire, it’s very easy to do, whereas, if you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation.

In rear hub motors, the motor pushes the bike forward and it’s very familiar for people since the majority of bikes are built that way.
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Old 12-04-19, 08:09 AM
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Originally Posted by nfmisso View Post
I have no ground clearance worries for my commuting - and would choose the TSDZ2 over any other conversion, because of the torque sensor system and its low weight.

If ground clearance is a concern, neither BaFang nor Tong Sheng are good choices because they hang down below the BB.
I thought hard about front/mid/rear drives when I was planning the e-conversion of my wife's bike. I ended up buying a Tong Sheng TSDZ2 kit and am very happy that I did. It's small, has adequate power, and best of all, it's a torque sensing system, which makes it more of a bicycle since you will have to pedal. The motor does hang down below the bottom bracket; however it does not hang below the bottom of the chain ring so clearance is moot.

Originally Posted by YuriyLogvin View Post
In my experience, when choosing a motor location I first, ask whoís going to be using the bike. Is this going to be a bike for a young or elderly person?

For older people, installing the motor on the front wheel is more beneficial. For young people, itís better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.
This observation about the age of the rider is inane. What basis do you have for making this distinction?
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Old 12-04-19, 10:08 AM
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This observation about the age of the rider is inane. What basis do you have for making this distinction?
This observation was based purely on the fact that different people have various riding needs and various levels of the desire to spend time maintaining their bikes.

The front-wheel usually is less loaded, and there's a chance that it might slip. The rear wheel is usually more heavily loaded. This gives us better pulling power.

Since elderly people have a calm riding style in general and don't need to develop high speeds, the front-hub motor position is more beneficial here. It's much easier in maintenance and gets the job done.
If you have a rear hub drive, youíll have to disassemble quite a lot do perform such a basic operation as changing a tire, for elderly people this can be a real time sink and a hassle.
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Old 12-04-19, 10:41 AM
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Pay attention to battery location as well. I can't stand the feeling of those big batteries mounted on rear racks. Throws the ride off rather badly. Lower and more centered is definitely better.
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Old 12-04-19, 11:08 AM
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Yes, as linberl mentioned, the battery location is important.
The rear rack battery location may be reasonable if the motor is installed in front. Then you get a more uniform distribution of the weight of the bike.

Another reason why people may install the battery at the back is that the length of the wires is reduced in this case.

However, probably the most effective location of the battery would be somewhere in the middle of the frame triangle. This arrangement most evenly distributes the weight on the bicycle frame.
Unfortunately, the disadvantage of this location is that it really complicates battery maintenance. The battery replacement can take much longer time.
But again, there are so many different bikes and frames, so each situation can be completely unique.
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Old 12-04-19, 06:59 PM
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Originally Posted by YuriyLogvin View Post
This observation was based purely on the fact that different people have various riding needs and various levels of the desire to spend time maintaining their bikes.
Yes, this is correct; however you take it a step further and assign these riding needs arbitrarily to age groups. Not a good practice to profile people, mate.

Originally Posted by YuriyLogvin View Post
Since elderly people have a calm riding style in general and don't need to develop high speeds, the front-hub motor position is more beneficial here. It's much easier in maintenance and gets the job done.
If you have a rear hub drive, you’ll have to disassemble quite a lot do perform such a basic operation as changing a tire, for elderly people this can be a real time sink and a hassle.
Your stereotypical generalizations are both odd and off-putting in this age of active seniors. You obviously have not ridden with the many "elderly" cyclists that I've met over the last decade. And why would maintenance be any more of a time sink/hassle for old folk than young, when the real factors are experience and the right tools.

Last edited by Moe Zhoost; 12-04-19 at 07:03 PM.
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Old 12-04-19, 08:27 PM
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I favour mid-drive systems in purpose-built ebike frames, with derailleur or IGH rear wheel, and with standard bike stem, handlebars, etc. Yes, the frame is bulkier and the whole system is more expensive - but the rest of the components are relatively inexpensive when (not if!) they need replacement.

My shop had a bit of a nightmare with several Stromer e-bikes this past summer.... Not only do they have extremely heavy rear wheel hub drives, but many of their models have a proprietary all-in-one stem and handlebar that was subject to a recall last summer. It was AWFUL.

Then I spent $60 replacing my own e-bike's cassette, chain, and brake pads. (Bosch mid drive system with derailleur). So cheap! So easy! No waiting for weird parts to come from Germany! I can lift the bike into a work stand without 3 helpers or a hydraulic lift!
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Old 12-04-19, 09:35 PM
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Originally Posted by YuriyLogvin View Post
In my experience, when choosing a motor location I first, ask whoís going to be using the bike. Is this going to be a bike for a young or elderly person?

For older people, installing the motor on the front wheel is more beneficial. For young people, itís better to mount the motor on the rear wheel. In that way, the wheel will not slip, the bike will have good dynamic characteristics.

In front hub motors the motor drives the front wheel and you can add to that by applying pedal power. If the motor is installed in the front hub, then the wheel can sometimes slip because the front wheel is less loaded.
One big advantage of the front hub motors is that they have a simple design. If you need to change the tire, itís very easy to do, whereas, if you have a rear hub drive, youíll have to disassemble quite a lot do perform such a basic operation.

In rear hub motors, the motor pushes the bike forward and itís very familiar for people since the majority of bikes are built that way.
As the one who started this thread and one with more gray than black hair - OK, no black hair anymore, I take no offense and appreciate the information. He IS correct. Some seniors with better health than I have been blessed with may not act their age, and more power to them!
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Old 12-05-19, 03:07 PM
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Manufactured ebikes will generally have the right kind of forks for a fronnt wheel mount, Home built ebikes should avoid them unless the builder understands where you go wrong. This picture was taken by a kit builder using a 359W motor, Luckilty for him, he wrote that his bike was stopped when the wheel fell off. It lasted for 15 minutes.



I have an ebike with aluminum forks and a 350W motor, and it has dual torque arms. After seeing the above picture, I get nervous all over again. I've marked the axle nuts with a sharpie pen, and they haven't moved.

That's why I think do-it-yourself people should just avoid the issue and use steel forks or a rear drive kit.

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Old 12-05-19, 06:08 PM
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Probably you're safe with dual torque arms; I wouldn't consider a front hub system on anything but steel forks and then use a torque arm too.
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Old 12-05-19, 09:47 PM
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I looked a little harder today and found a chrome-moly7 (steel) 20" fork with disk brake capability and a really long stem. I ordered it.
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Old 12-06-19, 12:38 AM
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There's a guy on MTBR that has a front hub motor on a carbon fork. He got really pissed at me when I said that the combination seemed unsafe.
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Old 12-06-19, 10:23 AM
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Unles you're running something big, like 500w, you're fine with a quality steel fork and no torque arms. 500w or more, I personally wouldn't put on the front, anyway. But the 250w/300w units are okay as long as you know the steel fork is in good condition.
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Old 12-06-19, 12:36 PM
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I have a 1500w (30 amp, 52V) front hub bike; steel fork, one torque arm, with a rear coaster brake, although I'll be adding a front cantilever soon. Great for road riding at 30 mph or so.
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Old 12-10-19, 06:48 PM
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Originally Posted by 2old View Post
I have a 1500w (30 amp, 52V) front hub bike; steel fork, one torque arm, with a rear coaster brake, although I'll be adding a front cantilever soon. Great for road riding at 30 mph or so.

I beg your pardon, you have a COASTER BRAKE? on an e-bike??? and you are "considering" a cantilever on the front, but you don't currently have anything stopping you and your motorcycle-size engine* except a coaster brake?


I hope you have good life insurance. That's honestly one of the more terrifying things I have ever read on here, or encountered in 7 years as a full time pro mechanic. There is absolutely nothing about this scenario which is remotely safe. That isn't a personal attack, it's a statement of fact.


Coaster brakes are not very strong in the first place; they are used on very low end bicycles, mainly kids' bikes. They are subject to overheating and failure at the kind of speeds you are describing - especially with the added mass of a motor, battery, and adult rider.

https://www.sheldonbrown.com/coaster-brakes.html


*In Alberta, a bicycle fitted with an electric motor of anything over 500W is legally a motorcycle and is subject to licensing and registration.
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